Current image sensors include a pixel unit array and a color filter unit array disposed over the pixel unit array. Each color filter unit in the color filter unit array covers a corresponding pixel unit. Each pixel unit includes a plurality of photosensitive pixels. In operation, the image sensors may be controlled to be exposed to light and output a merged image. The merged image includes a merged pixel array. The plurality of photosensitive pixels of a same pixel unit are merged into a merged photosensitive pixel for output. In this manner, a signal to noise ratio of the merged image can be increased. However, resolution of the merged image is decreased. The image sensors may also be controlled to be exposed to light and output a color block image of a higher pixel number. The color block image includes an original pixel array. Each photosensitive pixel outputs a corresponding original pixel. However, because a plurality of original pixels corresponding to a same color filter unit have a same color, resolution of the color block image is still not enhanced. Therefore, the color block image of the higher pixel number needs to be converted into an imitating image of the higher pixel number through interpolation. The imitating image may include a plurality of imitating pixels arranged in a Bayer pattern. The imitating image may be converted into a true color image. Through interpolation, clarity of the true color image may be enhanced, however, at higher resource and time consumption costs, which result in a longer image taking time and a poor user experience.